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USA | |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. |
| Eckel, Edwin Butt , Cobban, Robert R., Mosburg, Shirley K., Foord, Eugene E. (1997) Minerals of Colorado. Fulcrum Publishing. Irving, J. D. (1905) Bulletin Vol. 260, Ore Deposits of the Ouray District, Colorado. US Geological Survey p.50-77. doi:10.3133/b260 U.S. Geological Survey Professional Paper 1753 |